For blow molds, in particular for blow molding or stretch-blow molding containers of plastics, such as beverage bottles, a structural principle has become prevalent in which the mold support parts, to which the mold parts are mounted, actively perform the manipulations of the blow mold controlled by the actuation mechanism, while the mold parts remain passive. The mold parts are only active during the molding process during which the mold support parts fulfill the locking function of the blow mold and take up and transmit forces. For the manipulations of the blow mold, certain structural features at the mold support parts are necessary by means of which forces can be introduced, removed or received, and for which the mold support parts require a relatively complex variety of molds. The mold support parts of the blow molds, for example of a stretch-blow molding machine, have been manufactured up to now from one single type of material, e.g. as steel castings or aluminum castings. The employed material is homogenous with a constant density and material structure in most cases. This results in a compromise between strength and weight, because, for example, steel involves a higher weight when it exhibits a higher strength, while aluminum, being of a lower weight, has a lower strength. It has to be taken into consideration here that short cycle times and high blow pressures involve quick movements and high forces, so that a compromise between the strength and weight of the mold support parts means an undesired disadvantage.
In a blow mold known from US 2010/0047375 A1, the mold support parts in which the mold parts, except for a bottom mold part, are mounted, are designed with a complex reinforcing rib structure outside, and in a central vertical region of each mold part, a ring segment having a conical outer surface is fixed outside via which, when the blow mold is closed, a circumferentially closed collar with a conical inner surface is axially slid on for locking the mold. No material specifications of the mold support parts are disclosed.
In a blow mold known from EP 1 995 038 A, the mold support parts are formed outside with reinforcing ribs spaced apart and perpendicular to the swiveling axis of the mold support parts which can be folded open and close relative to each other, the reinforcing ribs cooperating with components of the actuation mechanism. The reinforcing ribs are welded on or integrally formed with the mold support parts and contain, for example, bearing eyes for a swivel pin. No material specifications for the mold support parts are disclosed.
However, it is generally known in molds in the mold parts defining the mold cavity to reinforce highly loaded surface areas, e.g. in the mold parting plane or at a bottom mold part, with reinforcing materials, but not optionally provided mold support parts z.